Population geneticists have been aware of the enormous genetic variation at biochemical level in natural populations (including humans) for some ten years. No satisfactory interpretation of the biological significance of the subtle variations has been identified. The objective of this project is to discern association among various biochemical polymorphisms that might indicate their physiological or developmental effects. BIBLIOGRAPHIC REFERENCES: Langley, C.H.: Non-random associations between allozymes in natural populations of D. melanogaster. In the publication of the proceedings of the symposium "Measurement of Natural Selection," Denmark 1976, accepted for publication by Springer Verlag, NY, 1977.